A searched CASE expression uses one or more Boolean expressions to determine the resulting value to return.
boolean-expression is evaluated in the order in which it appears within the CASE expression. result is an expression that is type-compatible in the context where the CASE expression is used. When the first boolean-expression is encountered that evaluates to TRUE, result in the corresponding THEN clause is returned as the value of the CASE expression. If none of boolean-expression evaluates to true then result following ELSE is returned. If no ELSE is specified, the CASE expression returns null.
The following example uses a searched CASE expression to assign the department name to a variable based upon the department number.